Communication systems are well known and consist of many types including land mobile radio, cellular radiotelephone, personal communication systems, and other communication system types. Within a communication system, transmissions are conducted between a transmitting device and a receiving device over a communication resource, commonly referred to as a communication channel. To date, the transmissions have typically consisted of voice signals. More recently, however, it has been proposed to carry other forms of signals, including high-speed data signals. For ease of operation, it is preferable to have the data transmission capability overlay the existing voice communication capability, such that its operation is essentially transparent to the voice communication system while still utilizing the communication resources and other infrastructure of the voice communication system.
One such communication system currently being developed with transparent data transmission capabilities is the next generation Code-Division Multiple-Access (CDMA) cellular communication system, more commonly referred to cdma2000. Within such a communication system all remote unit and base station transmissions occur simultaneously within the same frequency band. Therefore, a received signal at a base station or remote unit comprises a multiplicity of frequency and time overlapping coded signals from individual remote units or base stations, respectively. Each of these signals is transmitted simultaneously at the same radio frequency (RF) and is distinguishable only by its specific encoding (channel). In other words, the signal received at a base-station or remote unit receiver is a composite signal of each transmitted signal and an individual signal is distinguishable only after decoding.
Remote unit data transmission within a cdma2000 communication system takes place by assigning the remote unit a high-speed data channel (referred to as a supplemental channel) and transmitting data as discussed above utilizing the supplemental channel. More specifically, when data transmission is requested, a remote unit is immediately assigned a common traffic channel (fundamental channel), and remains on the fundamental channel until a supplemental channel is available. Once available, data transmission occurs utilizing the supplemental channel. Once all data has been transmitted, all the data has been transmitted and acknowledged, or a specified length of time has passed, the supplemental channel is dropped, and the remote unit continues to communicate via the fundamental channel. If all of the data has not been transferred, or if some data needs to be retransmitted (due to receive errors), the supplemental channel must be re-accessed, and the remaining data transmitted.
Because the number of supplemental channels available within a communication system are limited, the ability to quickly re-access a supplemental channel may as well be limited due to several remote units contending for the available supplemental channels. In other words, once a supplemental channel is dropped, the continued transmission/re-transmission of data over a supplemental channel can result in a timely procedure of re-accessing a supplemental channel. The procedure can also take the form of holding the supplemental channel until an acknowledgement of the final data transmission is received. Therefore, a need exists for a method and apparatus for data transmission within a broad-band communication system that allows for faster data transmission and more efficient use of the supplemental channel than with prior-art methods.